* Proschofsky, consultant challenge company candidates
* Conwert to publish all candidates' names by Wednesday
* Proschofsky says has no ambition to oust Conwert CEO
By Georgina Prodhan and Angelika Gruber
VIENNA, April 15 (Reuters) - Rebel investor Alexander Proschofsky has put himself forward to join the board of Austria's Conwert, signaling more upheaval for the property firm whose management he has criticised in the past.
The 44-year-old founder of Cube Invest proposed himself and a German real-estate consultant as alternatives to the two candidates proposed by the company, who he said were too close to major shareholder Hans Peter Haselsteiner.
Proschofsky, who says he owns about 1.5 percent of Conwert and also has his own Vienna property portfolio, was a vocal critic of the former head of the administrative board, Johannes Meran, who announced his departure in November.
He wants Conwert to focus on its core German portfolio, which he said it tried to sell last year, and install a director who knows the German market like his candidate, Peter Hohlbein, a former management board chairman of BIH Berliner Immobilien.
"We have to create shareholder value by running this company properly," Proschofsky told Reuters in an interview. "This whole company has been dominated for the past two years by the fact that Haselsteiner wants some smaller company."
Conwert's diluted net asset value per share was 14.98 euros at the end of 2013, while its share price was 9.33 euros. Most Austrian and German real-estate companies trade at around net asset value.
An independent source with knowledge of the matter said Conwert held talks with at least one party to sell the portfolio, which accounts for three-quarters of all the company's property.
Asked about the talks, a company spokesman said: "Conwert's strategy is positioned towards growth in Germany."
He said Conwert would publish the list of all the candidates for directorships by Wednesday, ahead of the company's annual shareholder meeting on May 7, where a vote will be held.
Proschofsky said he had the support of shareholders owning at least 10 percent of Conwert.
Haselsteiner, a prominent Austrian businessman who owns 24 percent of Conwert, was chief executive of construction company Strabag until a year ago and is co-founder and major shareholder of private rail and bus operator Westbahn.
Proschofsky said he had no ambition to oust Conwert CEO Clemens Schneider, who was brought in on Meran's departure and most recently ran the holding company that owns Westbahn.
"If he manages to run this company, then that's all good," he said. "He can learn and he may have some value."
Conwert's candidates for the two vacant positions on the company's five-person administrative board are insolvency lawyer Alexander Schoeller and venture capitalist Martina Postl.
Schoeller is a previous board member of the ECO commercial real-estate group, which was bought by Conwert in 2010.
Postl is a former management board member of top.equity Unternehmensbeteiligungs AG, a venture capital and private equity firm on whose board Haselsteiner sat. (Reporting by Georgina Prodhan; Editing by Mark Potter and Tom Heneghan)