Although Jose Botelho de Vasconcelos said he only expected the next gathering of the 12-member Organisation of the Petroleum Exporting Countries to take place, as planned, in Vienna on March 15, he added the group could meet sooner if oil prices suddenly dropped.
Asked whether a fall in the price of Brent crude oil to below $45 per barrel would trigger an Opec meeting before March, he replied:
"We admit it could happen if (oil prices) drop below $40."
Opec, which pumps about a third of the world's oil, agreed to cut its output by 2.2 million barrels per day (bpd) last month in reaction to a slide of more than $100 in oil prices since July as the global economic slowdown slams energy demand.
The latest cut helped oil prices recover from recent lows on Friday, although prices remain much below the head of Opec's 2009 target of $75 per barrel -- a price Botelho de Vasconcelos says is necessary for oil exploration to be viable.
London Brent rose $2.98 to $48.37 a barrel on Friday and US crude settled up 2.80 at $46.47.
"A reference price of $75 per barrel enables us to maintain and develop our activity (...) and turn medium-to-long-term projects viable," Botelho de Vasconcelos, who is also Angolan oil minister, said.
Asked if Opec would carry out more cuts if prices did not reach $75 per barrel in March, he replied:
"We could continue to carry out more cuts."
He added that other oil-producing nations, such as Russia, Azerbaijan and Norway, which don't belong to Opec, were welcome to join as this would increase the impact of the decisions taken by the cartel.
"They have been invited. They have participated (in Opec meetings). It is in the interest of everyone that oil prices reach a certain level," said Botelho de Vasconcelos.