Australia's Transfield Services Ltd (TSE.AX), which runs the country's offshore refugee detention centers, said it won't negotiate with Spain's Ferrovial SA (FER.MC) over a $873.60 million takeover approach until it agrees not to buy its shares for three months.

Transfield told reporters after its annual general meeting on Wednesday that it will give the Spanish infrastructure giant over 200 pages of commercial information, but only if Ferrovial agrees to a confidentiality agreement and a "stand-still" agreement preventing it from trading its shares.

Madrid-based Ferrovial's Oct. 20 approach comes as it seeks to grow its services operations globally and move away from the crisis-hit Spanish construction sector. But the offer quickly hit a snag when the Australian firm said the A$1.95 ($1.70) per share offer was too low.

Then at Wednesday's meeting, Transfield upgraded its 2015 financial year earnings forecasts by 8 percent, ratcheting up pressure on the Spanish suitor to sweeten its offer.

Transfield wouldn't confirm media reports stating Ferrovial objected to its request for a confidentiality agreement, but said it would not give detailed commercial information for due diligence until it agreed to its terms.

"We have been preparing this information. It will be available to them to determine whether they can offer a price that might be attractive to our shareholders," Transfield Chief Executive Officer Graeme Hunt told reporters.

"We stand ready to do that if they can get their heads around what is a pretty typical approach."

Ferrovial is a competitor which wants to operate in the same markets as Transfield so a confidentiality agreement is a standard request, Hunt added. "We could be competing with this company if this thing falls over down the track."

A Ferrovial spokesman in Australia could not immediately be contacted for comment.

Transfield shares closed 2 percent higher at A$1.90 in a flat overall market, below Ferrovial's offer of A$1.95 per share. The shares hit their highest level in 19 months after Ferrovial made its initial approach.