The outlook on the long-term rating has been revised to 'Negative' from 'Stable', it said in a statement.
"The revision in outlook reflects the weakening of key credit metrics due to higher than anticipated leveraging following higher capex, rise in loans and advances to related/unrelated parties, lower than anticipated volume growth in FY16 largely following lower coal volumes and deferment of upfront SEZ income," it explained.
The short-term rating on a Rs 6,700 crore commercial paper/short-term debt programme has also been reaffirmed at 'A1+', the statement said.
The ratings continue to factor in the strong business risk profile of APSEZ, characterised by its favourable operating characteristics, geographically spread out footprint, diversified cargo/geographic mix and long-term customer tie-ups, it said.
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However, it said the company - which has seven operational assets of which many depend on coal for growth - may continue to witness pressure on coal volume growth in the near-term.
Apart from this, iron ore exports and higher fertiliser imports would also support cargo volumes.
On the leveraging front, it said debt at 4.8 times the pre-tax profit was higher for a company in this rating category.
The advances to group and unrelated parties grew by Rs 973 crore during the fiscal year to Rs 4,500 crore, it said.
It will have to fund the construction of the Vizhinjam Port in Kerala for Rs 4,100 crore and the acquisition of the Katupalli port, it said.
The APSEZ scrip was trading 0.47 per cent up at Rs 225.80 a piece on the BSE, as against a 0.65 per cent correction in the benchmark at 1456 hrs.