UPDATE 3-YPF meeting dispute fuels tensions with Argentina

* Gov't has been pressuring YPF and others to boost output

* State board member says officials denied access to meeting

* YPF says company rules mean only board members allowed in

BUENOS AIRES, Feb 23 (Reuters) - A new dispute erupted between Argentina's government and YPF on Thursday when officials accused the oil company of denying them entry to a board meeting and threatened to take legal action.

YPF, controlled by Spain's Repsol, has been bearing the brunt of pressure from President Cristina Fernandez's administration for big energy companies to boost oil and natural gas output as fuel imports soar.

Officials have accused YPF and other oil firms of overcharging for diesel, and speculation that some sectors of Fernandez's government would like to renationalize YPF hit its shares late last month. Last week, the AFIP tax agency banned YPF from exports and imports over unpaid taxes.

Tensions flared again on Thursday after the state's representative on YPF's board of directors, Roberto Baratta, told reporters he and three other government officials had been refused entry to a board meeting.

"We don't know why YPF made this decision," said Baratta, who works at the Planning Ministry, calling it absurd and threatening legal action without giving further details.

YPF said company rules mean only board members - in this case Baratta - are allowed to take part in board meetings, adding that all four of the officials were invited to wait in the building to meet Chief Executive Sebastian Eskenazi and Repsol Chairman Antonio Brufau afterward.

Baratta was accompanied by Energy Secretary Daniel Cameron, Deputy Economy Minister Axel Kicillof and another official from the Planning Ministry.

"They decided to leave," YPF said in a statement.

The country's stock exchange regulator, the CNV, sent a letter to the energy compant asking it to explain what had happened before Thursday's board meeting, state news agency Telam reported.

YPF, which has a market value of about $14.4 billion, is the biggest energy company in Latin America's No. 3 economy and accounts for about 40 percent of the country's production of natural gas and crude.

YPF shares ended virtually unchanged at 159.5 pesos in Buenos Aires after dipping earlier in the session.