Japan and the European Union are at a crucial moment in their attempt to sign a free trade deal, Japan's foreign minister said Wednesday, with tariffs on European cheese a key sticking point.

The comments from Fumio Kishida come after four years of talks, with negotiators working toward signing a deal at a G20 meeting in Hamburg next week.

The influential Nikkei newspaper said EU Trade Commissioner Cecilia Malmstrom and agriculture commissioner Phil Hogan may come to Tokyo for meetings with their counterparts on Friday.

"This week and next week is the most important period so we must communicate at the ministerial level," Kishida told a forum.

"It's important to have a face-to-face meeting at an important moment... either they come here or we go there."

The European Commission said Hogan "stands ready to engage with Japanese counterparts whenever the ongoing discussions require a direct involvement at the political level".

Clinching the long-awaited deal would be a victory for free-trade advocates after US president Donald Trump pulled the United States out of the Trans-Pacific Partnership this year, dealing a possibly fatal blow to the mooted 12-nation deal.

The chief EU and Japanese trade negotiators have been holding "informal" talks in Tokyo this week.

Any deal they reach would cover some 28 percent of global GDP.

Among the key issues, Brussels wants Japan to eliminate its 30 percent tariffs on some EU-made cheese, while Tokyo wants duties cut on cars which it exports to the 28-member bloc.

"I hope to hold a summit meeting with the EU and reach a basic agreement" at the G20 talks, Japanese Prime Minister Shinzo Abe said in a recent speech.

"The Japan-EU Economic Partnership Agreement will be a model for 21st century economic order."