WELLINGTON, Feb. 11 -- Valentine's Day, the international day for lovers, is causing a thorn in the side of New Zealand rose growers.

As the price of red roses shoots up, the country's Flower Growers Association (FGA) is calling on the nation's lovers to ask where their roses come from and urging the government to level the competition against subsidized imports.

FGA Chairman David Blewden said Tuesday that about half the 600, 000 roses sold for Valentine's Day would come from overseas -- mostly from the two main source countries of India and Colombia -- but they would also carry risks to New Zealand biosecurity, health and jobs.

Although the imports could be significantly cheaper than the locally grown blooms, buyers could be disappointed, Blewden told Xinhua in a phone interview.

"To get the imports into the country, the roses have to be dipped in a herbicide for 20 minutes -- that's going to kill the flower or potentially affect the vase-life," he said.

People who were sensitive to chemicals would also need to be careful when handling the flowers.

"If the buyer gets an unsatisfactory experience, they might lump New Zealand flowers into the same category and it would cost us sales."

Even with the herbicide treatment, the imports could still carry exotic pests and diseases that are a threat to New Zealand's wider horticulture sector and could undermine the local industry's preference for biological -- rather than chemical -- treatments.

While New Zealand growers faced a labor-intensive and "daunting " challenge in producing roses for Valentine's Day, growers in India were given "a lot of incentives and subsidies" from planting through to transport for exports, said Blewden.

"New Zealand flower growers are strong advocates for free trade, because we also export, but in this case, we don't believe there is a level playing field," he said.

While tariffs to compensate for foreign subsidies "would be nice," he said, he was not confident of any government action.

"A lot of the retailers are very concerned to be supporting the domestic flower industry, because potentially the domestic industry could be lost and they would have to rely on imports all year round, but they are also feeling the pinch from their competitors as well."

Blewden said the sale of roses was strongly influence by supply and demand.

He had heard that a bunch of 10 long-stem red roses had fetched more than 30 NZ dollars (25 U.S. dollars) at auction on Monday, but "tomorrow that might be 90 NZ dollars (75 U.S. dollars) or 100 NZ dollars (83 U.S. dollars)."