By Alexis Akwagyiram and Felix Onuah

LAGOS (Reuters) - Leaders of a Nigerian trade union whose members are on strike held talks with government officials on Monday aimed at resolving the dispute, the Nigerian National Petroleum Corporation (NNPC) and a union leader said.

The strike by about 10,000 Petroleum and Natural Gas Senior Staff Association of Nigeria (PENGASSAN) members, including refinery workers and office staff, began on Thursday over issues the union said were "critical to the survival of the oil and gas industry in the country".

The industrial action has raised fears there could be fuel shortages in the OPEC member country which last week prompted NNPC to caution the public against panic fuel purchases.

There have been no signs of fuel shortages so far and, although the strike is being enforced by PENGASSAN members, workers from other trade unions such as Nigeria Union of Petroleum and Natural Gas Workers (NUPENG) are not involved.

NNPC spokesman Garba Deen Muhammad and PENGASSAN'S acting general secretary Lumumba Okugbawa said talks took place on Monday afternoon.

"The meeting was fruitful," Emmanuel Ibe Kachikwu, minister of state for oil, said of the six-hour talks with union leaders at NNPC's headquarters in the capital, Abuja.

PENGASSAN's president, Francis Johnson, said there had been "a very robust engagement" and added that the union's leaders would meet on Tuesday to "take some decision" on the industrial action.

The union said it decided to strike over issues such as joint venture funding and cash call arrears, which it said had stalled the creation of new jobs and investment in the sector.

Cash calls are the government's financial obligations to joint venture projects between NNPC and international and local oil companies.

A petroleum ministry source said these issues were discussed along with pay disputes and reforms to be carried out once the Petroleum Industry Bill is passed into law.

The bill, which has been in the works for a decade to overhaul the industry, will call for environmental, tax and revenue-sharing rules.

The strike comes as Nigeria's energy sector contends with a spate of attacks by militants on oil and gas facilities in its southern Niger Delta region over the last few months which briefly pushed oil production this spring to 30-year lows.

Earlier this year petrol shortages caused lengthy queues for motorists seeking to fill their tanks after fuel importers struggled to find dollars to pay for refined oil products due to central bank foreign exchange restrictions.

(Editing by David Evans and James Dalgleish)