Surviving on just tea, coffee and water, nine restaurant, bar and nightclub owners are on the sixth day of a hunger strike outside Portugal's parliament in protest against coronavirus restrictions.

"We need support ... to keep our heads above water," said Alberto Cabral, who runs a nightclub.

The protesters say they will not eat until they can meet the prime minister and economy minister. They are camping outside parliament and living on drinks donated by their supporters. One more business owner joined their strike on Sunday.

Bars and nightclubs have been closed since March and while restaurants were allowed to reopen in May, a curfew and weekend lockdown in place across most of the country since November 8 has angered restaurateurs, who say many of their businesses will not survive the year.

"It's just insolvencies," restaurant owner Joao Sotto Mayor said. "Many businesses depend on this time ... it's incredibly important that next weekend we return to normal opening hours."

An online petition by the movement behind the strike is gathering steam, with nearly 45,000 signatures so far and gaining several thousand each hour.

In compensation for weekend lockdowns, the government offered restaurants 20 percent of their average revenue between January and October of this year.

Owners say this is nowhere near enough. "How can we sustain a company that isn't earning any money but has to pay taxes, pay for light, water?" asked Jose Gouveia, a nightclub owner and spokesman for the movement.

The number of people registered as unemployed jumped 34.5 percent in October, from last year's figures, with around 72 percent of the newly unemployed working in restaurants or retail, according to government data.

"Everything is dying here in Portugal," Gouveia said.