* NAV up nearly 50 pct to 2.66 bln stg in year through Dec
* Adjusted NAV per share up 38 percent to 290 pence
* Market value of portfolio up 14.9 pct to 6.57 bln stg
* Shares up 16 percent, hit more than four-year high (Adds CEO comments, updates shares)
By Paul Sandle
LONDON, March 28 (Reuters) - The strength of London's property market was thrown into sharp relief on Friday as Songbird Estates Plc, main owner of the Canary Wharf estate in east London, said the estimated value of its buildings and planned developments had jumped by nearly half in the past year.
Songbird shares leaped more than 14 percent to their highest level in more than four years after its full-year results and portfolio valuation beat analyst forecasts.
Parts of central London have experienced sharp rises in property prices in recent months on the back of resurgent economic growth and demand from overseas buyers.
Songbird Chief Executive David Pritchard dismissed prospects of an unsustainable "bubble" in London residential property prices, pointing to population projections for the city indicating it would grow by 1 million people by 2020.
While prices could fluctuate, "that long-term demand suggests that there will be a long-run underpinning of values," Pritchard said.
Yet the risk of overheating in property prices remains a concern to the Bank of England, which on Thursday urged banks to consider the risk of interest rate hikes when they approve mortgages and said it was preparing tools to rein in potentially dangerous lending.
House prices in England and Wales have risen by around 5 percent over the past year and in London they are up around 14 percent, according to Land Registry data, and some commentators argue that parts of London's housing market are already in a bubble.
Songbird, also a part owner of the landmark "Walkie Talkie" skyscraper in the City, London's traditional main financial district, said on Friday its net asset value (NAV) - a key measure for property companies reflecting the value of their buildings and projects - had grown by nearly 50 percent to 2.66 billion pounds ($4.4 billion) in the year through December.
The company said in a statement it was confident about the immediate prospects for the London real estate market.
"The development pipeline (of new buildings) is well positioned to take advantage of increasing demand and the prospect of a shortfall in supply of both prime commercial and residential space," it said on Friday.
The developer and property owner is best known for its commercial properties, but has been broadening the appeal of its Canary Wharf site beyond major banks and financial firms, with space dedicated to tech start-ups and plans for residential development.
Songbird is also developing a 20-acre site called Wood Wharf adjacent to Canary Wharf, whose cluster of skyscrapers built around London's former docks started springing up in the 1980s.
The new development consist of smaller office blocks, apartments and shops and the group said was planning to devote more of the site to residential than it initially planned.
A new planning application, which is under consideration, included 2.5 million square feet of residential space out of a total 4.9 million, Pritchard said.
The CEO said a number of factors had come together to produce the increase in net asset value, including more office space let, with occupancy rates rising to 97 percent, the highest since the financial crisis, and more demand for retail space, where yields had compressed as property values rose and footfall - or the number of store visitors - had grown.
"But what's also in these results is the future," Pritchard said. "We put in planning applications last year for 9 million square feet. The market is recognising that long-term strategic move, both in terms of the space and the broadening out of the nature of the business - it's not just banks any more, it's moving towards residential."
Shares in Songbird, which counts Qatar Investment Authority and China Investment Corp as major shareholders, rose to a more than four-year high of 235 pence and were trading up 16 percent at 224.5 pence by 1429 GMT.
Analysts at JPMorgan Cazenove said the group had delivered "outstanding full-year results", with NAV per share coming in 26 percent ahead of their expectation of 230p. Underlying pretax profit of 22.4 million pounds was also ahead of expectations, they said.
Songbird said its adjusted NAV per share increased 38 percent to 290p. The market value of its total portfolio rose 14.9 percent to 6.57 billion pounds, it said. ($1 = 0.6019 British Pounds) (Editing by David Holmes)