It is untrue to say that the investment environment in China is worsening, said Chinese Premier Wen Jiabao Saturday as he invited more foreign companies to invest in the country.

China sticks to its opening-up policy, Wen added.

In talks with heads of prestigious German and Chinese firms in northwest China's Xi'an city, Wen and visiting German Chancellor Angela Merkel aim to boost cooperation between the two nations.

"Currently, there is an allegation that China's investment environment is worsening. I think it is untrue," said Wen when answering a question from Juergen Hambrecht, chief executive of German chemical company BASF.

Foreign firms have voiced concern China's indigenous innovation policy might provide incentives for government bodies to purchase products developed by Chinese companies.

The World Bank in a July report gave China a low investment environment ranking.

But the amount of foreign direct investment (FDI) that flowed into China in the first half of the year rose 19.6 percent year on year, according to data from the Ministry of Commerce (MOC).

China attracted 12.51 billion U.S. dollars in FDI in June alone, up 39.6 percent year on year.

Wen said, "Foreign investment will not pour into a country where the investment environment is worsening."

Wen said China has relatively good infrastructure as well as fair and stable market environment.

Wen said China welcomes companies which meet China industry policies to invest in China, adding that the government will ensure such companies having access to the Chinese market.

"For those which have entered China, they all enjoy national treatment as Chinese companies do, no matter whether they are a foreign-funded company, a joint venture or a joint stock company, " Wen said.

Wen also promised China would never block the export of rare earth minerals to foreign countries, but said minerals should be exported at a reasonable price and volume. China supplies about 90 percent of the world's rare earth minerals.

The trade seminar came after China and Germany Friday signed ten deals in Beijing involving green energy, culture and a joint venture producing trucks.

The two sides also signed a joint declaration on the establishment of an environmental partnership that will involve water resource protection, equipment safety and evaluation, energy conservation, renewable energy and technology.

"China-Germany cooperation is at a new starting point," Wen said.

After the seminar, Wen and Merkel visited China-German joint venture Siemens Signaling Company Ltd.

Merkel started a four-day visit to China on Thursday, her fourth trip to China since taking office as German Chancellor in 2005.