(Repeats story from late Friday)
* Fico warns relations with Hungary may deteriorate
* Keeps options open on make-up of next government
By Martin Santa and Jan Lopatka
BRATISLAVA, Feb 19 (Reuters) - Relations between EU neighbours Slovakia and Hungary could be seriously strained if the centre-right Fidesz party wins Hungary's April parliamentary election, Slovak Prime Minister Robert Fico said on Friday.
Fidesz leader and former prime minister Viktor Orban, whose party has a big lead in opinion polls, has said he wants to grant citizenship to Hungarians living abroad.
In addition to the half million-strong Hungarian population in Slovakia, there also are large Hungarian minorities in Romania and Serbia.
"If Fidesz begins to put into practice after getting into government what it declares now as an opposition party, then things will get bad," Fico told Reuters in an interview.
"I think that there will be great tension in 'neighbourly' relations," he added.
The leftist Fico is the frontrunner to win Slovakia's own election in June and the relations between the two countries may be an important factor in that vote.
Fico has been criticised in Europe for forming a government four years ago with the Slovak National Party, whose leader's nationalist rhetoric often has prompted protests in Hungary.
The Party of European Socialists suspended the membership of Fico's SMER party after the coalition was formed, but later lifted the suspension.
LANGUAGE LAW
Hungary protested against a language law adopted last year, which extended requirements to use Slovak along with Hungarian.
Fico said he had no plans to change the legislation. The Organisation for Security and Cooperation in Europe, a human rights watchdog, cleared the law but said it would monitor how it is used in practice.
Other incidents have soured ties. Hungarian President Laszlo Solyom was not allowed to enter Slovakia last August after being invited to attend an unveiling of a statue.
Last year Hungary demanded a probe into a Slovak police action after its special anti-riot units beat Hungarian soccer fans at a game in Slovakia, which was followed by protests in Budapest where demonstrators burnt a Slovak national flag.
Fico said he hoped such incidents would not be repeated but noted that tensions could rise again ahead of the Slovak vote.
"This can become the number one topic, an issue that will influence life in Slovakia and Hungary in the months to come," he said.
KEEPING ALL OPTIONS OPEN
Fico's SMER has dominated opinion polls ahead of the election, with support of around 40 percent, and he will most likely head any new government.
He said all options were open after the polls, including a SMER minority cabinet or a coalition with any of the opposition forces, including ethnic Hungarian parties.
But he also said he'd had a productive relationship with the partners in the existing coalition, the SNS as well as the HZDS party of former prime minister Vladimir Meciar, whose policies while in power resulted in isolating Slovakia internationally.
(Additional reporting by Krista Than in Budapest; Editing by Michael Roddy)